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UNIVERSITY    OF    ILLINOIS    LIBRARY    AT    URBANA-CHAMPAIGN 


L161—O1096 


ACES    SI 
JUN  1  6  2005 


UNIVERSITY  OF   ILLINOIS 


Agricultural  Experiment  Station. 


BULLETIN    NO.    TOO. 


DIRECTIONS    FOR   THE   BREEDING   OF   CORN, 
INCLUDING   METHODS   FOR   THE   PRE- 
VENTION   OF   IN-BREEDING 


BY  CYRIL  G.  HOPKINS,  LOUIE  H.  SMITH,  AND  EDWARD  M.  EAST. 


URBANA,    ILLINOIS,    MARCH,    1905. 


SUMMARY  OF  BULUETIN  No.  100. 

1.  Nine  years  of  corn  breeding  at  the  Illinois  Experiment  Station  have  proven 
the  possibilities  of  corn  improvement  in  both  yield  and  quality.  Page  601. 

2.  The  investigations  have  shown  that  continued  cross-breeding  by  detasseling 
alternate  rows  in  the  breeding  plot  increases  the  yield  of  corn  more  than  10  bushels 
after  the  first  year.  Page  610. 

3.  A  method  has  been  worked  out  and  adopted  which  gives  a  perpetual 
system  of  planting  designed  to  avoid  in-breeding.  Page  617. 

4.  All  seed  corn  selected  is  produced  by  cross-breeding.  Page  616. 

5.  Breeding  plots  should  be  started  with  the  best  obtainable  seed  corn.     It 
is  recommended  that  ninety-six  ears  be  planted  in  the  breeding  plot.     Plant  by 
the  row  system,  that  is,  corn  from  a  single  ear  in  each  row.  Page  614. 

6.  Examination  of  seed  corn  for  improvement  in  composition  may  be  made 
by  mechanical  methods  described.  Page  611. 

7.  The  Experiment  Station  offers  to  analyze  composite  samples  of  the  seed 
and  crop  from  breeding  plots  for  systematic  corn  breeders  of  Illinois.  Page  614. 

8.  Plant  corn  from  detasseled  rows,  according  to  a  guide  system  for  both 
"sire"  and  "dam"  seed.      Detassel  all  even-numbered  rows.     Select  seed  only 
from  the  best-yielding  detasseled  rows.  Page  619. 

9.  Mix  all  good  selected  seed  not  required  for  the  breeding  plot,  and  plant  in 
a  multiplying  plot.  Page  621 . 

10.  Plant  commercial  fields,  from  which  to  sell  pedigreed  seed  corn,  from 
the  best  seed  obtained  from  the  multiplying  plot.  Page  621. 

11.  Keep  a  pedigree  register  of  all  seed  ears  planted  and  of  all  rows  harvested 
in  the  breeding  plot.     The  Experiment  Station  will  furnish  blank  forms  to  any 
Illinois  farmer  who  wishes  to  become  a  seed  corn  breeder.  Page  620. 

12.  The  Illinois  Agricultural  Experiment  Station  has  no  seed  corn  for  sale. 

Page  623. 

13.  This  bulletin  will  be  sent  free  of  charge  to  any  one  interested  in  Illinois 
agriculture    upon   request   to   E.    Davenport,    Director,   Agricultural  Experiment 
Station,  Urbana,  Illinois;  and,  if  so  requested,  the  name  of  the  applicant  will  be 
placed  upon  the  permanent  mailing  list  of   the   Experiment   Station,  so  that  all 
bulletins  will  be  sent  to  him  as  they  are  issued. 


DIRECTIONS    FOR    THE    BREEDING   OF   CORN, 
INCLUDING   METHODS    FOR   THE   PRE- 
VENTION   OF    IN-BREEDING 

BY  CYRIL  G.  HOPKINS,  CHIEF  IN  AGRONOMY,  LOUIE  H.  SMITH,  CHIEF 

ASSISTANT  IN  PLANT  BREEDING,  AND  EDWARD  M.  EAST, 

FIRST  ASSISTANT  IN  PLANT  BREEDING. 

It  is  now  nine  yea/s  since  one  of  the  writers  began  investigations 
with  a  view  to  the  improvement  of  corn  by  breeding.  Credit  belongs 
to  Dr.  T.  J.  Burrill  and  to  Director  Eugene  Davenport  for  the  original 
suggestions  as  to  the  possibilities  of  such  improvement  and  its  impor- 
tance to  the  industries  related  to  corn.  The  investigations  have  included 
the  breeding  of  corn  for  increased  yield  and  for  improved  quality;  and 
the  results  which  have  been  achieved  have  far  surpassed  our  original 
expectations;  for  not  only  was  it  discovered  and  clearly  established  that 
corn  could  be  bred  for  increased  power  to  yield  and  for  higher  protein  con- 
tent or  higher  oil  content,  as  may  be  desired,  but,  as  soon  as  these  practical 
scientific  facts  were  fully  ascertained  and  the  methods  of  corn  breeding 
worked  out,  progressive  seed  corn  growers  of  Illinois  united  themselves 
into  the  world's  first  seed  corn  breeders  association,  and  at  once  began 
the  business  of  corn  breeding  on  a  commercial  scale.  Subsequently 
seed  corn  breeders  associations  have  been  organized  in  nearly  every 
important  corn-growing  state. 

The  Illinois  Seed  Corn  Breeders  Association  was  organized  in  1900 
and  began  breeding  corn  in  1901.  At  the  same  time  the  Illinois  Experi- 
ment Station  began  searching  for  possible  obstacles,  or  improvements, 
in  the  methods  of  corn  breeding  which  we  had  employed,  and  which 
had  been  adopted  by  the  commercial  corn  breeders.  The  most  important 
improvement  which  we  have  thus  far  made  in  the  system  of  corn  breeding 
is  that  which  relates  to  the  prevention  of  in-breeding. 

In  the  row  system  of  corn  breeding,  in  which  each  field  row  is  planted 
with  seed  from  a  separate  ear,  the  performance  record  of  the  plants  from 
each  individual  seed  ear  can  be  observed  and  accurately  measured;  and 
it  thus  becomes  possible  to  base  our  subsequent  seed  selected  upon  the 
performance  records  of  the  progeny  from  individual  mother  ears. 

In  this  system  of  planting  we  not  only  have  the  usual  possibility  of 
corn  being  self-pollinated,  but  we  have  an  unusual  possibility  of  consid- 
erable corn  being  close-pollinated.  (In  self-pollination  the  pollen  from 

601 


602  BULLETIN  No.  100.  [March, 

a  given  tassel  falls  upon  the  silk  of  the  same  plant.  In  close-pollination 
the  pollen  from  a  given  plant  falls  upon  the  silk  of  another  plant  in  the 
same  row,  both  of  which  grew  from  seed  from  the  same  mother  ear.  In 
cross-pollination  the  pollen  from  the  tassel  of  one  plant  falls  upon  the 
silk  of  another  plant  in  a  different  field  row,  which  grew  from  seed  from 
a  different  mother  ear.) 

Because  of  the  well-known  principle,  established  by  the  investiga- 
tions of  Darwin  and  others,  that  injurious  effects  are  produced  from  the 
self-pollination  of  plants  which  are  naturally  cross-pollinated,  many 
investigators  have  conducted  miscellaneous  detasseling  experiments  in 
corn  growing,  during  the  past  twenty  years  or  more.  The  plan  com- 
monly followed  has  been  to  detassel  alternate  rows  in  an  ordinary  corn 
field  and  to  compare  the  yields  of  the  tasseled  and  detasseled  rows.  The 
combined  data  from  all  such  experiments  point  tq  no  marked  effect  pro- 
duced by  detasseling. 

In  the  investigations  which  we  have  carried  on  at  the  Illinois  Station 
during  the  past  four  years,  including  one  year's  work  on  a  small  scale,  we 
have  systematically  detasseled  the  even-numbered  rows  in  breeding 
plots  and  have  then  successively  planted  the  even-numbered  rows  with 
seed  selected  from  the  best  detasseled  rows  and  have  planted  the  odd- 
numbered  rows  with  seed  selected  from  the  highest  yielding  tasseled  rows. 
For  three  years  this  system  has  been  practised  on  two  large  breeding 
plots,  containing  44  field  rows  in  each  plot,*  the  two  plots  being  conducted 
entirely  independent  of  each  other.  The  system  in  each  of  these  plots 
is  really  a  double  system,  one  set  of  22  rows  being  conducted  without 
detasseling,  in  all  respects  like  an  independent  breeding  plot  of  22  rows, 
the  seed  being  saved  each  year  from  the  10  highest  yielding  rows.  But 
alternating  with  these  tasseled  rows  were  detasseled  rows  of  corn,  which 
however  could  scarcely  exert  any  influence  upon  the  breeding  of  the 
tasseled  rows. 

On  the  other  hand,  the  22  detasseled  rows  are  necessarily  cross-bred 
each  year,  although  it  should  be  borne  in  mind  that  the  pollen  for  these 
detasseled  rows  was  always  furnished  by  the  22  tasseled  rows,  which  are 
themselves  becoming  more  or  less  in-bred.  If  benefits  are  produced 
from  this  imperfect  system  of  cross-breeding,  which  we  were  compelled 
to  adopt  in  order  to  obtain  comparative  data  from  alternating  rows  in 
the  same  field,  it  seems  probable  that  even  greater  benefit  will  result  from 
a  practical  commercial  system  which  we  have  now  adopted  in  which  the 
seed  for  both  sire  and  dam  is  cross-bred.  The  results  obtained  from 
three  years'  work  with  these  two  large  breeding  plots  are  given  in  detail 
in  Tables  1  to  6. 

For  detailed  comparison  there  are  given  from  every  individual  row 
in  each  plot  in  each  year  the  actual  yield,  the  actual  increase  in  yield, 

*Only  40  rows  the  first  year. 


1905]  DIRECTIONS  FOR  BREEDING  OF  CORN.  603 

the  percent  of  stand,  and  the  yield  and  increase  in  yield  calculated  to 
100  percent  stand.  Where  there  was  a  lower  yield  from  the  detasseled 
row  it  is  indicated  by  the  minus  ( — )  sign.  There  is  also  given  the  average 
of  the  tasseled  rows  and  of  the  detasseled  rows,  for  each  plot  and  for 
each  of  the  three  years,  1902,  1903,  and  1904.  The  register  number  and 
the  dam  number  of  each  seed  ear  are  given.  These  numbers  also  show 
the  field  row  in  which  each  ear  grew,  the  row  in  which  each  seed  ear  is 
planted,  and  the  number  of  years  it  has  been  bred,  as  fully  explained 
in  the  following  pages. 

For  example  the  last  row  in  the  high-protein  plot  in  1904  (see  Table  3) 
produced  100.8  bushels  of  corn,  actual  yield  per  acre,  with  96.4  percent 
stand,  which  would  make  104.6  bushels  if  calculated  to  100  percent 
stand.  The  register  number  of  the  seed  ear  which  was  planted  in  this 
row  is  344,  which  means  year  3  in  the  history  of  its  breeding  and  row  44 
in  which  it  was  planted.  This  seed  ear  was  produced  the  previous  year 
(year  2  of  its  breeding)  in  row  34  of  the  breeding  plot  as  shown  by  the 
dam  number  234.  Referring  to  Table  2  we  find  that  row  34  produced 
80.8  bushels  of  corn  per  acre  in  1903,  and  that  ear  234  grew  in  row  12 
the  previous  year,  as  shown  by  the  dam  number  112.  In  Table  1  we  see 
that  row  12  produced  88.5  bushels  of  corn  per  acre  in  1902.  Thus  we 
have  the  complete  pedigree: 

Ear  No.  344  (in  year  3,  row  44)  produced  100.8  bushels.  The  dam, 
Ear  No.  234  (in  year  2,  row  34)  produced  80.8  bushels.  The  grand 
dam,  Ear  No.  112  (in  year  1,  row  12)  produced  88.5  bushels. 

The  results  reported  in  columns  3  and  6  in  the  tables,  under  the 
heading  "Bushels  increase  by  detasseling"  are  obtained  by  comparing 
the  weight  of  each  row  with  the  average  of  the  two  adjoining  rows,  ex- 
cept with  the  first  and  last  rows,  which  are  compared  with  the  one  adjoin- 
ing row. 


604 


BULLETIN  No.  100. 


[March, 


TABLE  1.     EFFECT  OF  DETASSELING;    FIRST  YEAR'S  BREEDING. 
High-Protein  Learning;    Mechanical  Selection;    Grown  in  1902. 


Dam 
No. 

Register 
No. 

Calculated  to 
actual  stand.  • 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 

bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

101 
102 
103 
104 

81.8 
74.3 
82.5 
83.5 

'  -7.5 
-7.9 
-3.6 
49 

97.5 
94.5 
97.0 
99.6 

83.9 
78.6 
85.1 
83.8 

-5.3 
-5.9 
-3.9 
3.4 

105 
106 
107 
108 

74.6 
82.6 
86.4 
86.0 

85 
2.1 

-2.1 
32 

98.7 
96.2 
97.5 
96.2 

75.6 
85.9 
88.6 
89.4 

14.3 
38 
-0.9 
1.3 

109 
110 
111 
112 

79.1 
85.6 
81.3 

88.5 

6.7 
5.4 
58 
5.3 

90.3 
99.1 
97.0 
98.3 

87.6 
86.4 
83.8 
90.0 

0.3 
0.7 
4.4 
5.5 

113 
114 
115 
116 

85.1 
88.0 
78.4 
85.0 

3.2 
6.2 
8.1 
3.5 

100.0 
99.1 
99.6 
98.7 

85.1 
88.8 
78.7 
86.1 

4.3 
6.9 
8.8 
41 

117 
118 
119 

120 

84.5 
87.1 
81.1 
89.2 

-1.4 
-1.7 
4.1 
56 

99.1 
96.2 
89.8 
99.1 

85.3 
84.3 
90.3 
90.0 

O.I 

-3.5 
-3.1 
1.7 

121 
122 
123 
124 

86.0 
89.4 
88.0 
84.1 

3.3 
2.4 

-1.2 
-3.6 

99.6 
100.0 
100.0 
98.3 

86.3 
89.4 
88.0 
85.6 

3.4 
22 

-0.5 

-7.5 

125 
126 
127 
128 

87.3 
85.6 
80.4 
86.9 

-2.4 
1.7 
5.9 
6.5 

89.0 
99.6 
98.7 
96.2 

98.1 
85.9 
81.5 
90.3 

-12.3 
-3.9 
6.7 
7.0 

129 
130 
131 
132 

80.4 
84.2 
78.3 
76.3 

5.2 
48 
20 

-1.8 

94.5 
98.7 
94.5 
100.0 

55.1 
85.3 
82.9 
?6.3 

2.7 
13 

-2.1 

-5.5 

133 
134 
135 
136 

77.9 
85.1 
86.9 
80.8 

28 
2.7 

-3.9 

-4.6 

96.6 
98.7 
99.1 
98.3 

80.6 
86.2 

87.7 
82.2 

07 
20 

-3.5 

-3.8 

137 
138 
139 
140 

83.9 
78.3 
86.1 
81.9 

-4.3 
-6.7 
-6.0 
-4.2 

99.6 
95.3 
97.5 
100.0 

84.2 
82.2 
88.3 
81.9 

-2.0 
-4.1 
-6.2 
-6.4 

Average  of  detasseled,             84.1 
Average  of  tasseled,                82.5 

85.4 
85.3 

Average  increase,                       1  .  6 

0.1 

1905] 


DIRECTIONS  FOR  BREEDING  OF  CORN. 


605 


TABLE  2.— EFFECT  OF  DETASSELING;   SECOND  YEAR'S  BREEDING. 
High-Protein  Learning;   Mechanical  Selection;   Grown  in  1903. 


Dam 
No. 

Register 
No. 

Calculated  to 
actual  ctand. 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

103 
122 
117 

108 

201 
202 
203 
204 

63.3 
60.4 
51.0 
70.5 

-2.9 
3.2 
14.5 
17.9 

98.6 
96.8 
90.9 
97.3 

64.2 
62.4 
56.1 
72.5 

-1.8 
22 
II.  4 
16  1 

135 
114 
103 
126 

205 
206 
207 
208 

54.1 
70.0 
60.6 

75.7 

16.2 
12.6 
12.3 
15.9 

95.5 
98.2 
97.3 
99.1 

56.7 
71.3 
62.3 
76.4 

15.2 
11.8 
11.6 
14.7 

117 
108 
135 
114 

209 
210 
211 
212 

58.9 
70.0 
55.2 
68.1 

14.0 
12.9 
13.9 
6.0 

96.4 
98.6 
94.1 
96.4 

61.1 
71.0 

58.7 
70.6 

12.6 
III 
12.1 
6.0 

107 
126 
121 
108 

213 
214 
215 
216 

68.9 
76.8 
37.4 

77.7 

3.6 
23.6 
39.9 
26.1 

97.7 
95.0 
50.9* 
95.9 

70.5 
80.8 
73.5 

81.0 

5.2 
88 
7.4 
9.9 

137 
116 
107 
128 

217 
218 
219 
220 

65.8 
73.6 
63.9 
67.4 

99 
87 
66 

-1.9 

95.9 
98.6 
96.4 
95.9 

68.6 
74.6 
66.3 
70.3 

92 
7.1 

62 

-0.6 

121 
110 
137 
116 

221 
222 
223 
224 

74.7 
74.0 
56.8 
71.5 

-4.0 
82 
16  0 
2.2 

99.1 
98.6 
96.8 
95.9 

75.4 
75.0 
58.7 
74.6 

-2.7 
7.9 
16.1 
2.6 

107 
128 
123 
110 

225 
226 
227 
228 

81.8 
81.3 
56.3 
70.3 

-5.4 
12  2 
19  5 
10  4 

95.9 
98.2 
93.2 
96.4 

85.3 
82.8 
60.4 
72.9 

-6.6 
9.9 
17.5 
9.3 

139 
120 
113 

134 

229 
230 
231 
232 

63.4 
77.7 
54.8 
64.9 

10.6 
18  6 
16.5 
4.7 

95.0 
97.3 
94.5 
95.0 

66.7 
79.9 
58.0 
68.3 

9.7 
17.5 
16.1 
4.6 

125 
112 
123 
120 

233 
234 
235 
236 

65.6 
80.8 
51.5 
64.9 

7.3 
22.2 
21.4 
3.2 

94.5 
99.5 
93.2 
97.3 

69.4 
81.2 
55.3 
66.7 

5  4 
18.8 
18.7 
28 

139 
112 
125 
120 

237 

238 
239 
240 

71.8 
69.4 
53.9 
65.0 

-4.1 
6.5 
13.3 
4.5 

99.1 
97.3 
96.4 
97.3 

72.5 
71.3 
55.9 
66.8 

-3.5 
7.1 
13.2 
4.5 

113 
134 
139 
122 

241 
242 
243 
244 

67.1 
73.8 
61.4 
81.2 

2.3 
9.5 
16.1 
19.8 

97.7 
95.5 
98.6 
98.2 

68.7 
77.3 
69.3 

82.7 

3.4 
8.3 
10.7 
13.4 

Average  of  detasseled,            72.0 
Average  of  tasseled,                61  .  9 

74.1 
64.8 

Average  increase,                    10.1 

9.3 

*  Yields  discarded  from  average  (one  row). 


606 


BULLETIN  No.  100. 


[March, 


TABLE  3. — EFFECT  OF  DETASSELING;   THIRD  YEAR'S  BREEDING. 
High-Protein  Learning;   Mechanical  Selection;   Grown  in  1904. 


Dam 
No. 

Register 
No. 

Calculated  to 
actual  stand. 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

219 
214 
213 
244 

301 
302 
303 
304 

81.5 
90.9 
75.7 
86.9 

94 
12.3 
13  2 
10.6 

97.7 
98.6 
98.2 
95.0 

83.4 
92.2 
77.1 
91.5 

88 
II.  1 
14  8 
10.9 

201 
208 
241 
234 

305 
306 
307 
308 

76.8 
100.0 
82.8 
90.1 

16.7 
20  2 
12.3 
10  5 

91.4 
98.6 
95.9 
98.2 

84.0 
101.4 
86.3 
91.8 

12.5 
16.2 
10.3 
9.2 

217 
242 
233 
208 

309 
310 
311 
312 

76.3 

88.5 
56.8 
91.5 

13.0 
21   9 
33.2 
22  2 

96.8 
98.6 
64.1* 
98.6 

78.8 
89.8 
88.6 
92.8 

12.0 
6.1 
2.7 
4.4 

213 
244 
237 
222 

313 
314 
315 
316 

81.8 
96.5 
76.7 
88.9 

12  2 
17  2 

16  0 
4.3 

92.7 
94.1 
95.9 
98.6 

88.2 
102.6 
80.0 
90.2 

9.5 
18  5 
16  4 
3.5 

225 
214 
229 

242 

317 
318 
319 
320 

92.5 
95.6 
83.0 
89.2 

-0.2 
78 
9.4 
84 

99.1 
97.7 
97.7 
98.2 

93.3 

97.8 
85.0 
90.8 

0.7 
86 
93 
79 

221 
216 
225 

222 

321 
322 
323 
324 

78.6 
79.2 
80.1 
96.4 

5.6 
-0.2 
7.7 
12  6 

97.3 
94.1 
95.0 
97.3 

80.8 
84.2 
84.3 
99.1 

6.7 
1.6 
7.4 
11.3 

219 
230 
229 

218 

325 
326 
327 
328 

87.5 
91.6 
78.7 
94.0 

65 
85 
14  1 
II.  0 

95.9 
98.2 
94.1 
98.2 

91.2 
93.3 
83.6 
95.7 

50 
59 
10.9 
92 

237 
226 
221 
218 

329 
330 
331 
332 

87.2 
94.0 
90.7 
89.0 

6.8 
5.0 
08 
46 

97.7 
97.7 
98.6 
97.3 

89.3 
96.2 
92.0 
91.5 

6.7 
55 
19 
56 

213 
234 
217 

214 

333 
334 
335 
336 

78.0 
100.8 
82.2 
97.0 

16  9 
20.7 
16  7 
116 

97.7 
98.2 
96.4 
97.7 

79.8 
102.7 
85.3 
99.3 

17  3 
20   1 
15  7 
10  5 

241 
230 
201 
226 

337 
338 
339 
340 

88.5 
79.8 
95.2 
93.7 

-0.1 
-12.1 
-8.4 
50 

95.9 
87.7 
97.3 
97.3 

92.3 
91.0 
97.8 
96.3 

29 

-4.1 
-4.1 
50 

233 
216 
219 
234 

341 
342 
343 
344 

82.1 
83.5 
74.7 
100.8 

65 
5.1 
17  5 
26  1 

96.8 
90.9 
96.4 
96.4 

84.8 
91.9 
77.5 
104.6 

93 
10  7 
20  8 
27.1 

Average  of  detasseled,            91  .  7 
Average  of  tasseled,                82  .  4 

94.9 

85.4 

Average  increase,                       9.3 

9.5 

*  Yields  discarded  from  average  (one  row). 


1905] 


DIRECTIONS  FOR  BREEDING  OP  CORN. 


607 


TABLE  4. — EFFECT  OF  DETASSELING;    FIRST  YEAR'S  BREEDING. 
Low-Protein  Learning;    Mechanical  Selection;   Grown  in  1902. 


Dam 
No. 

Register 
No. 

Calculated  to 
actual  stand. 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

101 
102 
103 
104 

45.6 
41.6 
64.1 
52.3 

-4.0 
-13.3 
-17.1 
.-12.2 

80.5 
67.3* 

88.1 
84.7 

56.6 
61.8 

72.8 
61.8 

5.2 
-2.9 
-11.0 
-11.1 

105 
106 
107 
108 

64.8 
63.7 
66.4 
62.0 

-6.8 
-1.9 
-3.5 
-1.4 

88.9 
92.3 
90.0 
85.2 

72.9 
69.0 
73.8 

72.8 

-7.5 
-4.4 
-2.9 
1.4 

109 
110 
111 
112 

60.4 
53.4 
58.5 
54.5 

-2.7 
-6.1 
-4.5 
-2.6 

87.7 
77.9* 
48.7* 
83.5 

69.8 
68.5 
120.1 
65.3 

1.8 

-26.0 
-53.2 
-30.5 

113 
114 
115 
116 

55.7 
61.8 
56.1 
61.4 

2.5 
5.9 
5.5 

-1.7 

77.9* 
88.6 
83.5 
90.7 

71.5 
69.8 
67.2 

67.7 

-3.9 
0.4 
1.6 
-3.3 

117 
118 
119 
120 

70.0 
57.2 
71.0 
60.6 

-10.7 
-12.3 
-12.1 
2.9 

93.6 

85.2 
86.0 
86.0 

74.8 
67.1 
82.6 
70.5 

-7.4 
-11.6 
-13.8 
-9.6 

121 
122 
123 
124 

44.3 
50.1 
45.2 
61.2 

II.  1 
5.3 
10.5 
16.1 

57.2* 
87.7 
60.2* 
86.9 

77.5 
57.1 
75.1 
70.4 

-13.7 
-19.2 
-11.3 
1.6 

125 
126 
127 
128 

45.0 
50.0 

45.8 
47.2 

10.6 
4.6 
2.8 
2.8 

72.0* 
77.5* 
80.5 
73.7* 

62.5 
64.5 
56.9 
64.0 

5.0 
48 
7.4 

-0.6 

129 
130 
131 
132 

42.9 
48.4 
53.8 
41.5 

4.9 
0.0 

-8.8 
-17.4 

59.3* 
83.9 

75.8* 
69.5* 

72.3 
57.7 
71.0 
59.7 

-11.4 
-14.0 
-12.3 
-11.9 

133 
134 
135 
136 

64.0 
50.4 
57.7 
53.6 

-18.0 
-10.5 
-5.7 
-4.9 

88.6 
84.7 
84.7 
83.1 

72.2 
59.5 
68.1 
64.5 

-17.6 
-0.7 
-6.1 
-5.2 

137 
138 
139 
140 

59.2 
56.1 
64.4 
56.8 

-4.3 
-5.7 
-7.9 
-7.6 

83.1 
83.1 
84.3 
74.1* 

71.2 
67.5 
76.4 
76.7 

-5.2 
-6.3 
-4.3 
0.3 

Average  of  detasseled,            56.6 
Average  of  tassel  ed,                60.7 

65.8 
70.4 

Average  increase,                    -5.9 

-5.4 

*  Yields  discarded  from  average  (thirteen  rows). 


BULLETIN  No.  100. 


[March, 


TABLE  5. — EFFECT  OF  DETASSELING;   SECOND  YEAR'S  BREEDING. 
Low-Protein  Learning;   Mechanical  Selection;   Grown  in  1903. 


Dam 
No. 

Register 
No. 

Calculated  to 
actual  stand. 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

103 
114 
109 
124 

201 
202 
203 
204 

59.4 

83.7 
58.2 
82.5 

24.3 
24.9 
24.9 
11.9 

72.7* 
94.1 
91.4 
87.7 

81.7  . 
88.9 
63.7 
94.1 

7.2 
16.2 
27.8 
15.0 

119 
106 
103 
116 

205 
206 
207 
208 

85.0 
100.4 
69.6 
69.9 

6.5 
23.1 
15.6 

-2.6 

90.0 
98.2 
72.3* 

75.5* 

94.4 
102.2 
96.3 
92.6 

3.8 
6.8 

|!a 

109 
124 
133 
106 

209 
210 
211 
212 

75.4 
100.7 
93.6 
74.6 

9.9 
16.2 

-5.9 
-7.9 

96.4  . 
100.0 
90.9 

87.7 

78.2 
100.7 
103.0 
85.1 

18.1 
10.  1 

-10.1 
-7.1 

111 
138 
105 
108 

213 
214 
215 
216 

71.3 
92.7 
43.4 
112.6 

12.4 
35.3 
59.3 
52.9 

87.7 
96.8 
85.5 
98.6 

81.3 
95.8 
50.8 
114.2 

8.2 
29.7 
54.2 
48.0 

111 
116 
133 

108 

217 
218 
219 
220 

76.0 
93.8 
87.2 
83.3 

27.2 
12.2 
1.4 
24.9 

93.2 
96.4 
90.0 
72.3* 

81.5 
97.3 
96.9 
115.2 

24.3 
8.1 

9.4 

18  4 

137 
118 
105 
138 

221 
222 
223 

224 

29.5 
104.5 
87.8 
94.4 

64.4 
45.8 
11.7 
19.3 

30.5* 
94.1 
92.7 
94.5 

96.7 
111.1 
94.7 
99.9 

16.6 
15.4 
10.8 
1.7 

107 
116 
137 
114 

225 
226 
227 
228 

62.4 
96.9 
85.5 
82.6 

33.3 
22.9 
4.3 
0.2 

61.4* 
94.1 
94.5 
93.6 

101.6 
103.0 
90.5 
88.3 

-0.1 
-6.9 
5.2 
3.0 

117 
120 
109 
106 

229 
230 
231 
232 

.  79.3 
81.9 
79.0 
81.3 

3.0 
2.7 
2.6 
3.7 

99.1 
93.2 
89.5 
88.2 

80.0 
87.9 
88.3 
92.2 

8.1 
3.7 
1.8 

-6.9 

139 
120 
139 
112 

233 
234 
235 
236 

76.2 
100.2 
59.4 
73.9 

14.6 
32.4 
27.7 

-0.5 

92.7 
95.9 
65.5* 
77.3* 

82.2 
104.5 
90.7 
95.6 

16.2 
18.0 
9.4 
4.0 

117 
140 
107 
118 

237 
238 
239 
240 

89.4 
92.9 
82.3 
97.8 

-6.0 
7.0 
13.1 
32.4 

96.8 
96.4 
87.3 
93.2 

92.4 
96.4 
94.3 
104.9 

3.6 
3.0 
6.4 
13.6 

139 
112 
119 
140 

241 
242 
243 
244 

48.5 
30.0 
32.2 
95.5 

15.4 
-10.4 
30.6 
63.3 

55.0* 
24.1* 
29.5* 
98.6 

88.2 
124.5 
109.2 
96.9 

26.5 
25.8 
1.5 

-12.3 

Average  of  fletasseled,           92  .  7 
Average  of  tasseled,               78.0 

98.0 
84.8 

Average  increase,                    14.7 

14.2 

*  Yields  discarded  from  average  (eleven  rows). 


1905] 


DIRECTIONS  FOR  BREEDING  OF  CORN. 


609 


TABLE  6. — EFFECT  OF  DETASSELING;  THIRD  YEAR'S  BREEDING. 
Low-Protein  Learning;   Mechanical  Selection;   Grown  in  1904. 


Dam 
No. 

Register 
.      No. 

Calculated  to 
actual  stand 

Percent 
of  stand. 

Calculated  to 
100  percent  stand. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

Corn, 
bushels 
per  acre. 

Bushels 
increase 
by  detas- 
seling. 

219 
210 
231 
226 

301 
302 
303 
304 

56.3 
73.2 
61.7 

84.7 

16.9 
14  2 
17.3 
25.4 

90.0 
97.7 
94.1 
96.8 

62.6 
74.9 
65.6 
87.5 

12.3 
10  8 
15.6 
23.6 

205 
244 
219 
234 

305 
306 
307 
308 

56.8 
73.1 
69.6 
68.2 

22.1 
9.9 
II 

-0.4 

91.4 
95.5 
93.6 
93.2 

62.1 
76.5 
74.4 
73.2 

19.9 
82 
05 

-1.0. 

227 
224 
231 
218 

309 
310 
311 
312 

67.5 
80.2 
64.3 
77.3 

6.7 
14.3 
14.5 
4.3 

91.4 
97.3 
93.2 
96.4 

73.9 

82.4 
68.8 
80.2 

3.9 
II.  0 
12.5 
3.0 

237 
244 
211 
234 

313 
314 
315 
316 

81.7 
63.0 
68.3 
81.3 

-11.5 
-15.0 
3.9 
16.6 

95.5 
78.6* 
93.2 
94.6 

85.5 
80.2 
73.3 
85.9 

-5.3 
0.8 
9.9 
15.3 

223 
218 
229 
224 

317 
318 
319 
320 

61.1 

88.8 
79.5 

72.8 

24.0 
18.5 
1.3 

-0.6 

90.0 
96.8 
93.6 
96.4 

67.9 
91.7 
84.9 
75.5 

20.9 
15.3 
-1.3 

-2.4 

233 
210 
239 

226 

321 
322 
323 
324 

67.3 
91.2 
68.3 
85.7 

14.7 

23.4 
20.2 
29  7 

95.0 
100.0 
93.2 
95.9 

70.8 
91.2 
73.3 
89.4 

12.6 
19.1 
17.0 
11.7 

205 
240 
219 
222 

325 
326 
327 

328 

43.7 

86.4 
71.4 
74.8 

42.4 
28.8 
9.2 
5.9 

53.2* 
94.1 
95.0 
97.7 

82.1 
91.8 
75.2 
76.6 

8.5 
13  1 
90 
47 

227 
206 
231 

226 

329 
330 
331 
332 

66.4 
89.0 
59.3 
67.4 

15.5 
26  1 
18  9 

-0.6 

96.8 
98.6 
93.6 

81.8 

68.6 
90.3 
63.4 

82.4 

14.9 
24.3 
23.0 
II.  1 

237 
240 
211 
216 

333 
334 
335 
336 

76.7 
82.4 
69.7 

87.8 

-1.8 
9.2 
15.4 
20.3 

96.8 
96.4 
93.6 
98.6 

79.2 

87.1 
74.5 
89.0 

56 
10.2 
13.6 
17.3 

223 
210 
229 
222 

337 
338 
339 
340 

65.2 
78.4 
77.8 
85.9 

17.9 
69 
4.4 
9.3 

94.6 
95.9 
96.4 
96.4 

68.9 
81.8 
80.7 
89.1 

16.5 
7.0 
4.8 
7.7 

233 
206 
239 
216 

341 
342 
343 

344 

77.3 
80.2 
78.5 
83.9 

5.8 
2.3 
3.6 
5.4 

94.1 
92.7 
96.4 
95.0 

82.1 
86.5 
81.4 
88.3 

5.7 
4.7 
60 
6.9 

Average  of  detasseled,            80.6 
Average  of  tasseled,               68  .  8 

84.3 
73.2 

Average  increase,                    11.8 

11.1 

*  Yields  discarded  from  average  (two  rows). 


610  BULLETIN  No.  100.  [March, 

A  study  of  the  yields  of  individual  rows  shows  results  similar  to  those 
commonly  obtained  in  corn  breeding;  namely,  that  each  separate  mother 
ear  possesses  a  distinct  individuality  which  is  stamped  upon  the  offspring, 
as  shown  by  the  performance  record  when  the  yield  is  measured.  Thus, 
in  the  high-protein  plot  in  1902  row  5  produced  74.6  bushels  and  row  7 
produced  86.4  bushels  per  acre;  and  in  1904  row  22  produced  79.2 
bushels  and  row  24  produced  96.4  bushels  per  acre. 

In  the  high-protein  plot  in  1902  the  average  of  all  tasseled  rows  is 
.82.5  bushels,  and  the  average  of  all  detasseled  rows  is  84.1  bushels, 
showing  an  average  increase  of  1 . 6  bushels  in  favor  of  detasseling.  On 
the  low-protein  plot  the  average  increase  was  minus  5.9  bushels.  Thus, 
the  first  year's  results  are  similar  to  those  commonly  reported  from  a 
single  year's  experiment  in  detasseling  corn,  no  uniform  effect  being 
produced.  On  the  contrary,  we  have  obtained  some  very  striking  results 
in  1903  and  1904,  when  we  have  the  effects  due  to  breeding  for  one  year 
and  two  years,  respectively.  In  1903  the  average  yield  of  44  tasseled 
rows  (including  both  plots)  was  70 . 0  bushels,  while  82 . 4  bushels  was  the 
average  yield  from  the  44  detassel^d  rows,  an  average  increase  of  12.4 
bushels  in  favor  of  detasseling.  In  1904  the  corresponding  yields  were 
75.6  bushels  and  86.2  bushels  of  corn  per  acre,  making  an  average 
increase  of  10.6  bushels  in  favor  of  detasseling. 

This  evidence  in  favor  of  detasseling  the  rows  which  are  to  furnish 
future  seed  seems  so  conclusive  that  we  are  now  detasseling  alternate 
rows  in  our  corn  breeding  plots,  and  selecting  all  seed  ears  from  detasseled 
rows  only;  and,  in  order  to  obtain  the  greatest  possible  benefit  from 
cross-breeding  of  plants  of  no  relation  or  of  the  most  distant  relation, 
we  have  worked  out  and  adopted  a  mathematical  arrangement  of  seed 
ears  for  planting  which  is  designed  continuously  to  maintain  these 
desirable  conditions. 

"Corn  improvement  should  embrace  both  quantity  and  quality.  But, 
because  of  the  great  importance  of  increased  yield  per  acre,  all  selection 
looking  toward  improvement  should  be  first  based  upon  yield,  this  to 
be  followed,  so  far  as  practicable,  with  efforts  which  aim  toward  higher 
standards  of  quality.  It  is  with  these  ideas  that  the  following  methods 
for  corn  breeding  are  arranged. 

PHYSICAL  SELECTION  OF  SEED  CORN. 

The  most  perfect  ears  obtainable  of  the  variety  of  corn  which  it  is 
desired  to  breed  should  be  selected.  As  a  rule,  these  seed  ears  should  be 
obtained  from  some  reliable  seed  corn  breeder  in  preference  to  starting 
with  unknown  and  unimproved  corn. 

In  making  the  selection  for  desirable  ears,  as  judged  from  the  physical 
characteristics,  the  larger  the  number  of  ears  examined  the  better  can 
be  the  selection.  If  the  breeder  wishes  to  improve  the  quality  (chemical 


1905] 


DIRECTIONS  FOR  BREEDING  OF  CORN. 


611 


composition)  of  the  grain,  as  well  as  the  yield  and  type  of  his  corn,  it  is 
recommended  that  he  choose  at  least  200  ears  of  the  desired  physical 
type  to  be  further  examined  as  to  quality. 

CHEMICAL  SELECTION  BY  MECHANICAL  EXAMINATION. 

The  following  table  fairly  illustrates  the  results  obtained  by  the  use 
of  the  method  of  mechanical  examination  in  the  selection  of  high-protein 
seed  ears. 

TABLE  7. — RESULTS  OF  SELECTION  FOR  PROTEIN  IN  CORN  BY  METHOD  OF 
MECHANICAL  EXAMINATION.  ; 


Selected  by 

Total 
number 
ears 
examined. 

Ears  selected 
as  high  in  protein. 

Ears  Rejected  as 
not  high  in  protein. 

Number 
of  ears. 

Ave.  % 
protein. 

Number 
of  ears. 

Ave.  % 
protein.- 

111.  Exp.  Station  (1902) 
Ralph  Allen  (1902)  .... 
Ralph  Allen  (1903)  .... 
A.  L.  Woodhams  .  . 

200 
165 
225 
187 
200 
200 
134 

(?) 
4  bushels 

42 
15 
1-5 
36 
40 
25 
26 
24 
14 

12  14 
13.56 
13.15 
11.59 
10.94 
11.59 
11.37 
10.64 
11.71 

:  42* 
150 
210 
151 
160 
175 
108 
(?) 
(?) 

10.67 
12.10 
11.51 
10  29 
10.88 
II  29 
10.78 
9.94 
9.70 

Hunt  Bros  

William  Berg  

H.  A.  Winter  

W.  G.  Griffith  

Ohio  Exp.  Station  

*  Selected  for  low  protein  from  same  lot  of  200  ears. 


The  success  of  this  method  in  the  hands  of  several  practical  farmers 
is  demonstrated.  We  notice  that  m  every  case  there  was  a  gain  made 
in  average  protein  content  of  the  selected  ears,  and  in  some  of  these  cases 
the  gains  were  very  decided. 

METHOD  OF  MECHANICAL  EXAMINATION. 

The  method  of  making  a  chemical  selection  of  ears  of  seed  corn  by  a 
simple  mechanical  examination  of  the  kernels  is  based  upon  the  fact 
that  the  kernel  of  corn  is  not  homogeneous  in  structure,  but  consists  of 
several  distinct  and  readily  observable  parts  of  markedly  different  chemi- 
cal composition.  (See  Plates  1  and  2.)  For  a  complete  detailed  study 
of  "  The  structure  of  the  corn  kernel  and  the  composition  of  its  different 
parts,"  see  Bulletin  No.  87. 

For  our  particular  purpose  of  judging  from  the  structure  qf  the  kernel 
as  to  its  composition,  we  need  consider  but  three  principal  parts,  namely: 


612 


BULLETIN  No.  100. 


[March, 


HIGH-PROTEIN  KERNELS 
(Much  horny  part; 
little  white  starch). 


LOW-PROTEIN  KERNELS 
(Little  horny  part; 
mugh  white  starch). 


PLATE  1. 

1.  The  darker  colored  and  rather  horny  layer  lying  next  to  the  hull, 
principally  in  the  edges  and  toward  the  tip  end  of  the  kernel.  This  part 
is  fairly  rich  in  protein  and  contains  from  one-half  to  two-thirds  of  all 
the  protein  of  the  kernel.  (See  Plate  1.) 


1905] 


DIRECTIONS  FOR  BREEDING  OF  CORN. 


613 


HIGH-OIL  KERNELS 
(Large  germs). 


Low-OiL  KERNELS 
(Small  germs). 


PLATE  2. 


2.     The  white,  starchy-appearing  part  occupying  the  crown  end  of 
the   kernel   and   usually   also   immediately    surrounding,   or    partially 


614  BULLETIN  No.  100.  [March, 

surrounding,  the  germ.  This  part  is  poor  in  both  protein  and  oil,  con- 
sisting mainly  of  starch.  (See  Plate  1.) 

3.  The  germ  itself,  which  occupies  the  central  part  of  the  kernel 
toward  the  tip  end.  This  is  very  rich  in  oil..  More  than  four-fifths  of 
the  entire  oil  of  the  kernel  resides  in  the  germ.  It  is  also  rich  in  protein, 
containing  nearly  one-fifth  of  all  the  protein  in  the  kernel,  although  the 
germ  itself  constitutes  only  about  one- tenth  of  the  weight  of  the  kernel. 
(See  Plate  2.) 

In  selecting  seed  corn  by  mechanical  examination  for  improvement 
in  composition,  we  remove  from  the  ear  a  few  average  kernels,  cut  these 
kernels  into  cross  sections,  preferably  near  the  tip  end  of  the  kernel 
(see  longitudinal  sections),  and  examine  these  sections  as  they  are  cut, 
usually  simply  with  the  naked  eye,  selecting  for  seed  those  ears  whose 
kernels  show  the  qualities  desired. 

SAMPLES  FOR  ANALYSIS. 

In  order  that  the  breeder  may  know  what  he  has  accomplished  in  his 
work  of  mechanical  selection,  the  Experiment  Station  offers  to  analyze 
for  any  Illinois  farmer  who  wishes  to  improve  the  quality  of  his  corn  by 
breeding  according  to  these  directions  and  who  agrees  to  make  the  best 
selection  of  seed  possible,  two  composite  samples  representing  each  of  the 
two  lots  of  ears;  that  is,  the  selected  lot  and  the  rejected  lot. 

One  composite  sample  should  be  made  by  taking  10  average  kernels 
from  each  of  the  selected  ears  (96  ears  preferred),  and  another  sample 
should  be  made  by  taking  10  average  kernels  form  each  of  the  rejected 
ears  (100  ears  or  more).  Each  of  these  two  samples  should  be  put  in  a 
separate  sack,  properly  labeled,  and  sent  to  the  Plant  Breeding  Labora- 
tory, Agricultural  Experiment  Station,  Urbana,  111. 

Of  course,  if  the  breeder  desires  to  breed  for  physical  type  and  increased 
yield  only,  then  no  chemical  analysis  is  needed,  and  all  that  is  necessary 
to  begin  work  is  to  select  the  96  most  nearly  perfect  ears  obtainable 
for  the  breeding  plot. 

SIZE  OF  BREEDING  PLOT. 

The  best  number  of  ears  to  use  in  a  breeding  plot  is  as  yet  an  unsettled 
question.  There  are  several  conflicting  factors  entering  into  the  con- 
sideration. On  the  one  hand,  the  smaller  the  number  of  ears  taken,  the 
choicer  can  be  the  selection  of  the  seed  planted ;  while  on  the  other  hand 
the  larger  the  number  of  breeding  rows  to  choose  from,  the  better  can  be 
the  selection  of  seed  for  the  next  crop.  Then  again,  there  is  undoubtedly 
some  danger  of  evil  effects  from  too  close  in-breeding,  by  the  use  of  too 
small  a  number  of  ears. 

From  our  present  knowledge  we  believe,  however,  that  96  ears  is  a 
safe  number  to  use,  so  far  as  in-breeding  is  concerned,  and  this  is  the 


1905]  DIRECTIONS  FOR  BREEDING  OF  CORN.  615 

number  that  we  suggest  in  these  directions,  it  being  understood  that 
alternate  rows  are  to  be  detasseled  and  all  seed  corn  selected  from  de- 
tasseled  rows. 

PLANT  BY  THE  Row  SYSTEM. 

The  96  selected  seed  ears  are  planted  in  96  separate  rows.  These 
rows  should  be  at  least  100  hills  Ibng,  but  they  may  well  be  40  rods  long, 
as  the  amount  of  seed  will  usually  permit  this. 

It  is  recommended  that  these  96  seed  ears  be  numbered*  from  1  to 
48  and  from  51  to  98,  the  numbers  49  and  50  being  omitted;  also  that 
ears  1  to  48  be  planted  in  one  half  of  the  plot  and  ears  51  to  98  be  planted 
in  the  other  half,  preferably  end-to-end  with  the  first  half,  leaving  one 
hill  unplanted  to  mark  the  line  between  the  two  halves,  also  leaving  one 
row  unplanted  to  mark  the  line  between  rows  24  and  25  and  between 
rows  74  and  75;  that  is,  between  quarters. 

In  this  way  row  51  (planted  with  seed  from  ear  51)  is  a  continuation 
of  row  1  (planted  with  seed  from  ear  1)  and  the  two  rows  may  well  extend 
80  rods,  across  a  40-acre  field.  The  breeding  plot  can  be  planted  with  a 
corn  planter,  although  it  will  require  some  time  and  patience,  and  if  the 
planter  is  an  edgedrop  it  will  be  necessary  to  put  a  suitable  cone  or 
inverted  funnel  in  each  seed  box  so  as  to  keep  the  small  amount  of  corn 
to  the  outside.  Place  the  shelled  corn  from  ear  No.  1  in  one  box  and 
from  ear  No.  2  in  the  other;  drive  to  the  middle  line  of  the  plot,  thus 
planting  rows  1  and  2;  clean  out  the  boxes;  move  forward  one  hill;  put 
in  the  corn  from  ears  51  and  52;  use  the  foot- trip  till  the  corn  begins  to 
drop;  then  drive  on  and  plant  rows  51  and  52.  Turn  at  the  end;  clean 
out  the  seed  boxes ;  put  in  ears  53  and  54;  plant  back  to  the  middle ;  clean 
out,  put  in  ears  3  and  4,  and  then  plant  on  back  to  the  beginning  line, 
thus  continuing  until  the  breeding  plot  is  all  planted.  The  planting  may 
then  be  continued  for  the  commercial  field,  using  the  same  variety  of 
corn,  which  should  be  of  similar  breeding,  finishing,  perhaps,  with  the 
multiplying  plot  on  the  opposite  side  of  the  field  from  the  breeding  plot. 

Each  one  of  the  breeding  plot  rows  should  be  numbered  to  correspond 
with  the  "register  number"  of  the  ear  from  which  it  is  planted,  as  will  be 
explained  under  the  heading  of  "Pedigree  Register." 

The  breeding  plot  should  be  well  protected  from  foreign  pollen,  by 
being  planted  as  far  away  as  possible  from  other  varieties  of  corn. 

DETASSELING. 

From  the  data  which  we  have  secured  and  are  securing  upon  the 
subject,  we  now  strongly  recommend  that  every  alternate  row  of  corn 
in  the  breeding  plot  be  completely  detasseled  before  the  pollen  matures 

*  These  numbers  would  be  101  to  148  and  151  to  198  the  first  year,  201  to  248 
and  251  to  298  the  second  year,  etc.,  etc.  (See  under  Register  Number,  page  621.) 


616  BULLETIN  No.  100.  [March, 

and  that  all  of  the  seed  corn  to  be  taken  from  the  plot  be  selected  from 
these  48  detasseled  rows.  This  method  absolutely  prohibits  self-polli- 
nation or  close-pollination  of  the  future  seed.  By  self-pollination  is 
meant  the  transfer  of  pollen  from  the  male  flower  (tassel)  of  a  given  plant 
to  the  female  flower  (silk)  of  the  same  plant;  and  by  close-pollination  is 
meant  the  transfer  of  pollen  from  the  male  flower  of  one  plant  to  the 
female  flower  of  another  plant  in  the  same  row,  both  of  which  grew  from 
kernels  from  the  same  seed  ear.  It  is  recommended  that  no  plants  in 
any  of  the  rows  which  appear  imperfect,  dwarfed,  immature,  barren,  or 
otherwise  undesirable,  should  be  allowed  to  mature  pollen.  Occasionally 
an  entire  row  should  be  detasseled  because  of  the  general  inferiority  of 
the  row  as  a  whole.  Detasseling  is  accomplished  by  going  over  the  rows 
as  many  times  as  may  be  necessary  and  carefully  pulling  out  the  tassels 
as  they  appear.  Indeed,  great  care  should  be  exercised  in  this  part  of  the 
work  in  order  not  to  injure  the  plants  and  thereby  lower  the  yields.  The 
tassels  should  not  be  cut  off,  as  this  produces  an  external  injury  and  at 
the  same  time  the  stalk  is  often  deprived  of  several  undeveloped  leaves. 
But  the  tassel  should  be  allowed  to  develop  far  enough  so  that  it  can  be 
separated  alone  at  the  top  joint  by  a  careful  pull.  It  is  now  fully  deter- 
mined that  the  detasseling  of  the  breeding  rows  is  necessary.  This  insures 
cross-pollination  and  markedly  increases  the  yield  of  succeeding  crops. 

SELECTION  OF  FIELD  Rows  AND  SEED  EARS. 

As  the  crop  matures,  the  corn  from  each  of  the  detasseled  breeding 
rows  is  now  harvested.  First,  all  of  the  ears  on  the  row  which  appear 
to  be  good  ears  and  which  are  borne  on  good  plants,  in  a  good  position, 
and  with  good  ear  shanks  and  husks,  are  harvested,  placed  in  a  bag, 
with  the  number  of  the  row,  and  finally  weighed,  together  with  the 
remainder  of  the  crop  from  the  same  row.  No  seed  ears  should  be  taken 
within  two  or  three  rods  of  the  inside  ends  of  the  rows.  The  total  weight 
of  ear  corn  which  every  detasseled  row  yields  should  be  determined  and 
recorded,  for  the  yield  is  the  primary  factor  in  determining  the  rows  from 
which  all  of  the  ears  for  the  next  year's  seed  selection  must  be  taken. 
Each  lot  of  ears  from  each  of  the  detasseled  rows,  and  finally  each  single 
ear  of  the  96  seed  ears  ultimately  selected  is  kept  labeled  with  the  number 
of  the  row  in  which  it  grew  and  finally  with  its  own  ear  number  also,  and 
permanent  records  are  made  of  the  number  and  the  description  of  the 
ear,  the  performance  record  of  the  row,  etc.,  so  that  as  the  breeding  is 
continued  an  absolute  pedigree  is  established,  on  the  female  side,  for 
every  ear  of  corn  which  may  be  produced  from  this  seed  so  long  as  the 
records  are  made  and  preserved.  We  also  know  absolutely  that  we 
have  good  breeding  on  the  male  side,  although  the  exact  individual 
pedigree  of  the  males  cannot  be  known  and  recorded. 


19051 


DIRECTIONS  FOE  BREEDING  OF  CORN. 


617 


PLANTING  FOR  CROSS-POLLINATION. 

In  order  to  insure  cross-breeding  to  the  greatest  possible  extent  the 
plan  given  in  Table  8  should  be  adopted. 

TABLE  8. — PLAN  FOR  PLANTING  THE  BREEDING  PLOT  TO  AVOID  IN-BREEDING. 

The  numbers  given  in  the  "Guides"  designate  the  field  rows  from  which  the 
seed  ears  are  taken.     (All  even-numbered  rows  are  detasseled.) 


Field 
row 
No. 

Guide 
system 
for 
even 
years. 

Guide 

system 
for 
odd 
years. 

Model 
example 
for  an 

even 
year. 

Field 
row 
No. 

Guide 
system 
for 
even 
years. 

Guide 

system 
for 
odd 
years. 

Model 
example 
for  an 
even 
year. 

.   1. 

.  .76.. 

78... 

76 

51 

.    ...   2 

4 

4 

2. 
....  3. 
4. 
....  5. 
....   6. 
....   7. 
8. 

2.. 
80.. 
6.. 
84.. 
10.. 
78.. 
4.. 

2... 
82... 
....  6... 
....86... 
....10... 
....76... 
4..  . 

4... 
....84... 
....10... 
....90... 
....16... 
....80... 
8 

....52. 
....53. 
....54. 
55. 
....56. 
....57. 
58 

52.. 
6.. 
56.. 
10.. 
60.. 
4.. 
54 

....52... 
....  8... 
56... 
12... 
60... 
2... 
.      .   54 

....52... 
....10... 
....58... 
16... 
....66... 
....  8... 
56 

....  9. 
10. 
11. 
12. 

82.. 
8.. 
86.. 
..'...12.. 

....80... 
....   8... 
....84... 
12... 

....86... 
14... 
....92... 
20... 

....59. 
....60. 
....61. 
62. 

8.. 
58.. 
12.. 
62  .. 

6... 
....58... 
10... 
62  .  .  . 

14... 
....60... 
20... 
68  .  . 

13. 

78.. 

76..  . 

80..  . 

63. 

4  . 

.  .  .    .   2  . 

.    .  8 

14. 

2  . 

2..  . 

4 

64. 

52  . 

.  .  .    .52 

52  . 

15. 
16. 
17. 

82.. 
6.. 
86.. 

....80... 
....   6... 
84... 

....86... 

....10:.. 

92... 

....65. 
....66. 
67. 

8.. 
56.. 
12.. 

6... 
56... 
10... 

14... 
....58... 
20..  . 

18. 

10.. 

10..  . 

16.  .  . 

68. 

60.  . 

60.  .  . 

66..  . 

19. 

76.. 

78... 

76     . 

69. 

2.. 

4  .  . 

4.  .  . 

....20. 
....21. 
....22. 
23. 

4.. 
80.. 
8.. 
84.. 

4... 
....82... 
....  8... 
86..  . 

....   8... 
....84... 
....14... 
90.  .  . 

....70. 
....71. 
....72. 
73. 

54.. 
6.. 
58.. 
10.. 

54... 
8... 
58... 
12... 

....56... 
....10... 
....60... 
16... 

24. 

12.  . 

12... 

20.  .. 

74. 

62.. 

62..  . 

68..  . 

25. 

52.. 

..54.. 

.  .52.. 

.  .75. 

.  .26.. 

.  .28.. 

..30.. 

26. 

26.. 

26..  . 

30... 

76. 

76.. 

76... 

76... 

27. 

56.  . 

58... 

58..  . 

77. 

30.  . 

32..  . 

36... 

28. 

30.. 

30.  .  . 

36... 

78. 

80.. 

80... 

84... 

29. 

60.  . 

62 

66..  . 

79. 

34.  . 

36... 

42..  . 

....30. 
31. 

34.. 
54.. 

....34... 
52... 

42... 
56... 

....80. 
81. 

84.. 
28.. 

84... 
26..  . 

....90... 
34... 

32. 

28.. 

28..  . 

34..  . 

82. 

78.. 

78... 

80... 

33. 

58.  . 

56..  . 

60..  . 

83. 

32.. 

30... 

38..  . 

34. 

32.. 

32..  . 

38..  . 

84. 

82   . 

82..  . 

86..  . 

35. 

62.. 

60  .  . 

68..  . 

85. 

36.  . 

34... 

46..  . 

36. 

36.  . 

36  .  . 

46.  .  . 

86. 

86  . 

86.  .  . 

92... 

.  .  .37. 

54 

52 

56  .  . 

87. 

.    ...  28 

26  .  . 

34  .  ,  . 

38. 

26.. 

26..  . 

30..  . 

88. 

76.. 

76..  . 

76... 

39. 

58.. 

56..  . 

60.  .  . 

89. 

32.. 

30..  . 

38... 

40. 

30.. 

30..  . 

36.  .  . 

90. 

80.. 

80.  .  . 

84... 

41. 

62.. 

60.  .. 

68... 

91. 

36.. 

34... 

46..  . 

42. 

34.. 

34.  .  . 

42..  . 

92. 

84.  . 

84... 

90.  .  . 

43. 

52.. 

54.  .  . 

52... 

93. 

26.  . 

28..  . 

30..  . 

44. 

28.. 

28     . 

34 

94. 

78  . 

78..  . 

80... 

....45. 
....46. 
47. 

56.. 
32.. 
60.. 

58... 
32... 
62..  . 

....58... 
....38... 
66... 

....95. 
....96. 
97. 

30.. 
82.. 
34.. 

32... 
82... 
36..  . 

....36... 
....86... 
42..  . 

48. 

36.. 

36..  . 

46... 

98. 

86.. 

86..  . 

92... 

618  BULLETIN  No.  100.  [March, 

In  this  plan  the  breeding  plot  is  considered  by  quarters.  Each 
quarter  contains  24  rows  and  each  row  is  planted  with  corn  from  a  separate 
seed  ear.  All  even-numbered  rows  are  detasseled  and  seed  for  the  next 
year's  breeding  plot  is  taken  from  the  six  best-yielding  detasseled  rows  in 
each  quarter,  four  ears  being  taken  from  each  selected  row,  making  96 
ears  in  all. 

For  convenience  we  use  the  term  "sire  seed/'  or  "sire  ears,"  to 
designate  the  ears  which  are  to  be  planted  in  odd-numbered  rows  to 
produce  tassels  (the  male  flowers)  and  to  furnish  pollen;  and  we  use  the 
term  "dam  seed"  or  "dam  ears"  to  designate  the  ears  to  be  planted  in 
the  even-numbered  rows  to  produce  future  seed  ears.  Of  the  four  seed 
ears  taken  from  each  selected  field  row,  two  are  used  for  sire  seed  and 
two  for  dam  seed. 

In  the  column  headed  "Guide  system  for  even  years"  is  given  a 
key  or  guide,  by  which  to  work  out  the  actual  plan  for  planting  in  all 
even-numbered  years,  and  under  the  heading  "Model  example  for  an 
even  year"  is  given  an  actual  plan  which  has  been  worked  out,  using  four 
seed  ears  from  six  selected  rows  from  each  quarter  of  the  breeding  plot. 

In  the  guide  system,  for  the  sake  of  simplicity,  we  use  four  seed  ears 
from  each  of  the  first  six  even-numbered  rows  in  each  quarter,  a  selection 
which  would  probably  never  occur  in  actual  practice. 

It  will  be  observed  that  the  dam  seed  ears  for  each  quarter  are  ears 
which  grew  in  the  same  quarter,  while  the  sire  seed  is  always  brought 
from  another  quarter.  For  the  first  quarter  (rows  1  to  24) ,  sire  ears  are 
brought  from  the  fourth  quarter.  For  the  second  quarter,  sire  seed  is 
brought  from  the  third.  In  each  of  these  cases  sire  seed  is  carried  dia- 
gonally across  the  breeding  plot.  For  the  third  quarter  sire  seed  is 
brought  from  the  first  quarter,  and  for  the  fourth,  from  the  second,  the 
sire  seed  being  carried  lengthwise  of  the  breeding  plot  in  these  cases. 

It  will  also  be  observed  that  there  is  a  definite  order  of  planting  for 
"even  years"  and  another  definite  order  for  "odd  years."  Thus,  in  the 
first  quarter,  the  even-numbered  rows  are  planted  in  ascending  order 
with  dam  seed  selected  from  rows  numbered:  2,  6,  10,  4,  8,  12,  2,  6,  10, 
4,  S,  12. 

The  alternating  even  numbers  are  repeated  in  sets  of  three  and  six. 
The  odd-numbered  rows  are  planted  with  sire  seed  selected  from  rows 
numbered:  76,  80,  84,  78,  82,  86,  78,  82,  86,  76,  80,  84. 

This  is  the  same  order  as  for  the  dams  except  that  the  two  sets  of  three 
are  reversed  in  the  second  set  of  six.  The  only  change  required  for  odd- 
numbered  years  is  to  transpose  the  two  sets  of  six  in  planting  the  sire 
seed.  Exactly  the  same  system  is  used  in  each  quarter  of  the  breeding 
plot, 


19051  DlKECTlONS  FOR  BREEDING  OF  CORN.  619 

ARRANGING  SEED  EARS  FOR  PLANTING. 

By  referring  to  the  "Model  example  for  an  even  year"  it  will  be  seen 
that  it  becomes  an  easy  matter  to  follow  the  "Guide  system"  in  arranging 
seed  ears  for  planting.  Suppose,  for  example,  that  in  1905  the  best  six 
rows  in  the  first  quarter  of  the  breeding  plot  are  4,  8,  10,  14, 16,  20.  Then 
for  the  dam  seed  for  planting  the  first  quarter  in  1906  these  numbers,  in 
ascending  order,  are  to  be  substituted  for  the  numbers  2,  4,  6,  8,  10,  12, 
which  are  given  in  the  "Guide  system." 

Thus:  For  2,  substitute  4;  for  4,  substitute  8;  for  6,  substitute  10; 
for  8,  substitute  14;  for  10,  substitute  16;  for  12,  substitute  20. 

Arranging  these  for  planting  the  field  rows,  we  have: 


ROW 

GUIDE 

ACTUAL 

No. 

SYSTEM. 

PLAN. 

2 

2 

4 

4 

6 

8 

6 

10 

10 

8 

4 

14 

10 

8 

16 

12 

12 

20 

14 

2 

4 

16 

6 

8 

18 

10 

10 

20 

4 

14 

22 

8 

16 

24 

12 

20 

If  the  best  six  rows  in  the  fourth  quarter  of  the  1905  breeding  plot 
are  76,  80,  84,  86,  90,  92,  then  for  the  sire  seed  for  planting  the  first 
quarter  in  1906  these  numbers  are  to  be  substituted  in  regular  order  for 
the  numbers  76,  78,  80,  82,  84,  86,  which  are  given  in  the  "Guide  system." 
Arranging  these  by  threes  as  indicated  in  the  "Guide  system"  we  have 
the  order  for  planting  the  odd-numbered  rows  in  the  first  quarter:  76, 
84,  90,  80,  86,  92,  80,  86,  92,  76,  84,  90. 

Thus  we  have  both  the  dam  and  sire  seed  ears  for  the  first  quarter, 
arranged  exactly  as  shown  under  the  heading  "Model  example"  in 
Table  8.  The  seed  ears  are  arranged  for  each  quarter  of  the  breeding 
plot  in  a  similar  manner  by  following  the  "Guide  system"  and  substitut- 
ing in  regular  ascending  order  the  actual  numbers  of  the  best-yielding 
rows  for  the  numbers  given  in  the  "Guide  system"  in  Table  8. 

It  will  be  seen  that  with  this  selection  of  best  rows,  as  given  in.  this 
"Model  example,"  we  would  take  the  four  best  seed  ears  from  row  No.  4 
(1905)  and  plant  two  as  dam  ears  in  rows  2  and  14  and  the  other  two  as 
sire  ears  in  rows  51  and  69  (1906) ;  we  would  take  the  four  best  seed  ears 
from  row  No.  84  (1905)  and  plant  two  as  dam  ears  in  rows  78  and  90  and 
the  other  two  as  sire  ears  in  rows  3  and  21  (1906). 

In  arranging  seed  ears  selected  from  the  1906  breeding  plot  for  planting 
the  1907  breeding  plot,  we  are  to  follow  the  "Guide  system"  for  odd- 
numbered  years,  again  returning  to  the  system  for  even-numbered  years 
for  1908. 


620 


BULLETIN  No.  100. 


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Average  

1905]  DIRECTIONS  FOR  BREEDING  OF  CORN.  621 

MULTIPLYING  PLOT. 

Seed  for  a  multiplying  plot  of  ten  acres  or  more  should  be  taken  only 
from  the  selected  rows  of  the  breeding  plot,  and  may  include  all  good 
seed  corn  which  is  not  required  for  the  breeding  plot.  This  seed  should 
be  well  mixed  together  and  planted  on  the  multiplying  plot.  The  corn 
grown  in  the  multiplying  plot  should  be  carefully  protected  from  foreign 
pollen  and  all  inferior  stalks  may  be  detasseled.  The  exact  yield  of  the 
multiplying  plot  should  be  determined  and  registered. 

COMMERCIAL  FIELD. 

The  seed  for  the  commercial  field  should  be  only  the  best  obtainable 
seed  corn  from  the  multiplying  plot.  The  exact  yield  of  the  commercial 
field  should  be  determined  and  registered.  From  the  commercial  field 
the  finest  ears  may  be  selected  and  sold  to  the  trade  as  pedigreed  seed 
corn. 

PEDIGREE  REGISTER. 

The  Experiment  Station  has  adopted  a  form  for  registering  the  num- 
bers and  descriptions  of  all  the  seed  ears  used  in  corn  breeding  and  also 
for  recording  their  performance  records. 

In  this  form  there  is  provided  space  only  for  those  measurements  and 
data  which  now  seem  to  be  essential,  as  well  as  of  general  practicability 
in  breeding  up  valuable  strains  of  corn.  There  are  some  extra  columns 
which  may  be  used  for  any  special  points  upon  which  any  breeder  may  be 
working. 

DESCRIPTION  OF  INDIVIDUAL  EARS. 

REGISTER  NUMBER. — As  soon  as  any  ear  of  a  given  variety  and  strain 
is  selected  to  be  planted  in  a  breeding  plot  by  a  given  breeder  it  is  given  a 
"Register  Number,"  which  must,  of  course,  represent  that  particular  ear 
only  and  for  all  time.  By  using  a  certain  system  of  numbering  we  are 
not  only  able  to  accomplish  this  purpose,  but  can  show  at  the  same  time 
the  year  of  its  breeding  or  the  number  of  its  generation,  and  the  field  row 
in  which  it  is  planted.  This  we  do  by  starting  the  first  year  in  the  100 
series,  numbering  the  ears  to  be  planted  in  succession  from  101  to  148 
and  151  to  198,  and  the  second  year  starting  the  200  series,  running 
from  201  to  248  and  251  to  298,  and  so  on,  starting  each  succeeding  year 
with  a  higher  hundred. 

DAM  NUMBER. — The  "Dam  Number"  is  the  "Register  Number"  of 
the  parent  ear  and  is  useful  in  tracing  the  pedigree  record  from  year  to 
year  back  to  the  source. 

ANNUAL  EAR  NUMBER. — In  order  to  designate  the  200  or  more  ears 
selected  from  the  field,  each  one  is  given  an  "Annual  Ear  Number,"  which 
runs  in  a  series  from  1  up  to  200  or  more.  This  number  is  only  temporary, 


622  BULLETIN  No.  100.  [March, 

to  serve  while  working  on  the  corn  for  the  final  selection  of  seed  ears, 
and  when  the  seed  ears  are  selected  to  be  planted,  each  is  given  a  per- 
manent "  Register  Number,"  as  explained  under  that  heading. 

LENGTH  OF  EAR. — This  is  the  measurement  in  inches  of  the  total 
length  from  butt  to  tip. 

TIP  CIRCUMFERENCE  OF  EAR. — This  is  the  measurement  in  inches  at 
two  inches  from  the  tip  end  of  the  ear. 

BUTT  CIRCUMFERENCE  OF  EAR. — This  is  the  measurement  in  inches 
two  inches  from  the  butt  end  of  the  ear. 

NUMBER  OF  Rows  OF  KERNELS. — This  is  self-explanatory. 

NUMBER  OF  KERNELS  IN  Row. — This  is  the  average  number  of 
kernels  in  the  row  from  tip  to  butt. 

WEIGHT  OF  EAR. — This  is  taken  in  ounces  after  it  has  become  thor- 
oughly air-dried. 

WEIGHT  OF  COB. — This  is  taken  in  ounces  after  the  kernels  have  been 
shelled  off. 

TIP  CIRCUMFERENCE  OF  COB. — This  is  the  measurement  in  inches, 
two  inches  from  the  tip  end. 

BUTT  CIRCUMFERENCE  OF  COB. — This  is  the  measurement  in  inches, 
two  inches  from  the  butt  end. 

PERCENT  PROTEIN  IN  GRAIN. — There  are  being  bred  some  varieties  in 
which  every  individual  seed  ear  is  subjected  to  an  exact  chemical  analysis 
for  the  protein  content  of  the  grain,  and  this  column  is  provided  for  the 
result  of  such  tests. 

PERCENT  OIL  IN  GRAIN. — There  are  being  bred  some  varieties  in  which 
a  chemical  oil  test  is  made  of  each  individual  seed  ear,  and  this  column 
provides  for  the  records  of  such  data. 

PERFORMANCE  RECORD  OF  FIELD  Rows. 

PLANTED  IN  FIELD  Row  NUMBER. — The  field  row  or  breeding  row 
numbers  should,  for  the  sake  of  convenience,  correspond  with  the  register 
numbers  of  the  ears  planted;  for  example,  ear  "Register  No."  101  should 
be  planted  in  "Field  Row  No."  1. 

CORN  POUNDS  PER  Row. — The  total  yield  of  ear  corn  of  every  breeding 
row  of  the  plot  should  be  recorded  in  pounds. 

CORN  BUSHELS  PER  ACRES. — This  is  computed  from  "corn  pounds 
per  row,"  and  from  the  "distance  between  hills"  and  "number  of  hills 
in  row,"  as  recorded  in  the  upper  right  hand  corner  of  the  sheet.  The  full 
number  of  hills  per  row  should  always  be  used  in  this  computation  unless 
otherwise  noted.  The  number  of  pounds  per  bushel  should  be  estimated 
as  fairly  as  possible,  depending  upon  the  condition  of  the  crop  at  the 
time  of  harvest.  (Commonly  75  or  80  pounds  are  used  after  the  corn  is 
dry  enough  to  crib  safely.) 

NUMBER  OF  EARS  IN  Row. — This  includes  nubbins,  as  well  as  good 


1905]  DIRECTIONS  FOR  BREEDING  OF  CORN.  623 

ears.  The  total  weight  of  ears  and  the  total  number  give  sufficient  data 
to  determine  the  average  weight.  Some  breeders  also  desire  to  record 
the  number  of  good  seed  ears  produced.  Such  records  can  be  placed  in 
the  blank  columns. 

PERCENT  OF  PROTEIN  IN  GRAIN. — This  column  is  provided  for  those 
varieties  in  which  an  exact  chemical  control  is  being  kept  of  the  parent 
ears  and  their  offspring,  and  for  averages  when  seed  ears  are  selected  by 
mechanical  examination. 

PERCENT  OF  OIL  IN  GRAIN.— The  same  note  applies  here  as  above. 

On  the  same  sheet  with  the  complete  year's  record  of  the  breeding 
plot  appear  the  records  of  the  multiplying  plot  for  the  same  year,  and  for 
the  next  year  following,  and  also  the  records  of  the  commercial  field  for 
the  same  year  and  for  the  next  two  years.  If  the  record  sheet  is  for  the 
breeding  plot  for  1905  it  is  important  to  finally  record  on  the  same  sheet 
the  record  of  the  multiplying  plot  for  1906  and  of  the  commercial  field 
for  1907,  and  for  convenience  and  comparison  it  is  well  to  record  on  the 
same  sheet  the  yield  of  the  multiplying  plot  for  1905,  and  the  yields  of 
the  commercial  field  for  1905  and  1906.  If  a  breeding  plot  were  started 
in  1905,  the  breeder  could  have  both  a  breeding  plot  and  a  multiplying 
plot  in  1906,  and  a  breeding  plot,  multiplying  plot,  and  commercial 
field  in  1907;  and  from  the  1907  crop  on  the  commercial  field  he  could 
sell  seed  corn  with  a  registered  pedigree  of  three  years,  one  year  in  the 
breeding  plot,  one  year  in  the  multiplying  plot,  and  one  year  in  the 
commercial  field.  In  1910  he  could  sell  seed  corn  from  his  commercial 
field  with  a  registered  pedigree  of  six  years — four  years  in  the  breeding 
plot  (1905,  1906,  1907,  and  1908),  one  year  in  the  multiplying  plot  (1909), 
and  one  year  in  the  commercial  field  (1910). 

At  the  bottom  of  the  corn  register  sheet  is  a  space  under  "Remarks," 
in  which  any  irregularities  concerning  the  data  of  the  sheet  may  be 
explained;  or  there  can  be  placed  here  any  short  notes  that  it  may  be 
desirable  to  record  in  regard  to  the  soil  of  the  plot,  the  weather,  or  any 
other  conditions  affecting  growth. 

These  corn  register  sheets  may  be  secured  upon  application  to  the 
Experiment  Station  by  any  Illinois  farmer  who  wishes  to  start  a  breeding 
plot. 

THE  EXPERIMENT  STATION  HAS  NO  SEED  CORN  FOR  SALE. 

On  account  of  the  numerous  calls  that  are  constantly  being  received 
by  us  for  seed  corn,  it  is  thought  well  to  explain  here  that  the  Experiment 
Station  has  no  seed  of  any  kind  for  distribution.  It  is  the  particular 
province  of  the  Experiment  Station  to  investigate  and  to  demonstrate 
principles.  Others  make  the  commercial  application  of  these  principles 
whenever  they  are  proved  to  be  of  commercial  importance. 

For  the  sake  of  the  definite  knowledge  to  be  gained,  investigations 


624  BULLETIN  No.  100.  [March, 

are  often  carried  on  to  determine  what  we  should  avoid  doing  in  practical 
agriculture,  as  well  as  to  discover  what  we  should  do  for  improving  agri- 
cultural conditions  or  practices.  The  station  has  demonstrated  the 
possibility,  through  selection  and  breeding,  of  improving  corn  both  as  to 
yield  and  as  to  quality.  Marked  changes  have  been  produced  in  the 
composition  of  corn.  We  recognize  the  fact,  however,  that  there  may  be 
a  limit  beyond  which  these  changes  in  composition  cannot  be  carried 
without  interfering  with  the  physiological  functions  of  the  seed  and  plant 
to  the  extent  of  impairing  the  yield.  Therefore  these  experiments  are 
being  carried  on  still  farther  to  determine  if  possible  where  the  danger 
limits  lie,  in  order  that  we  may  be  able  to  point  out  such  limits  to  practical 
corn  breeders  who  follow  along  in  these  lines  of  corn  improvement. 

For  our  first  experiments  in  corn  breeding,  which  began  some  nine 
years  ago,  we  selected  a  variety  of  corn  of  medium  size  and  of  safe  maturity 
for  this  latitude  with  which  to  work  out  methods,  and  to  ascertain  the 
possibilities  of  corn  improvement.  This  variety  was  well  adapted  to  our 
purpose,  but  is  was  not  one  of  our  largest  or  highest-yielding  varieties  of 
corn.  This  preliminary  work  was  necessarily  carried  on  on  a  small  scale 
and  the  original  experiments  are  still  being  continued  on  about  the  same 
scale.  While  we  have  definitely  determined,  for  example,  that  the  protein 
of  corn  can  be  increased  by  breeding,  we  now  wish  to  determine  whether 
this  might  be  carried  to  such  an  extent  as  to  result  in  impaired  constitution 
or  vigor  of  growth  or  reduced  yield.  If  there  is  such  a  danger  point,  then 
the  Experiment  Station  should  discover  the  fact  before  it  is  actually 
reached  by  the  practical  corn  breeders. 

As  soon  as  we  had  demonstrated-  that  the  improvement  of  corn  by 
breeding  was  both  possible  and  practicable,  a  considerable  number  of 
the  most  successful  seed  corn  producers  in  Illinois  adopted  our  methods 
of  corn  improvement,  and  for  several  years  they  have  been  systematically 
breeding  corn  on  a  large  scale.  Thus  it  happens  that  while  the  methods 
and  principles  have  been  worked  out  and  demonstrated  by  the  Experi- 
ment Station  on  plots  of  small  area  and  with  corn  of  medium  size  and 
yield,  the  commercial  seed  corn  breeders  are  now  applying  these  principles 
to  hundreds  or  even  to  thousands  of  acres,  and  while  they  began  some 
years  after  the  first  experiments  were  undertaken  by  us,  they  began  with 
all  of  the  different  leading  varieties  of  corn  grown  in  the  state,  and, 
moreover,  they  are  breeding  different  varieties  of  corn  especially  adapted 
to  different  sections  of  the  state. 

Furthermore,  several  members  of  the  Illinois  Seed  Corn  Breeders 
Association,  recognizing  the  importance  of  producing  corn  especially 
adapted  to  special  purposes,  have  taken  up  the  work  of  improving  the 
quality  of  their  varieties  along  different  lines,  following  the  methods 
established  by  the  Experiment  Station.  Thus  they  are  breeding,  first, 
for  improvement  in  yield,  and,  second,  for  improvement  in  composition. 


1905]  DIRECTIONS  FOR  BREEDING  OP  CORN.  625 

Some  of  them  are  breeding  to  increase  the  protein  content,  and  others 
to  increase  the  oil  content  in  their  corn,  while  some  varieties  or  strains 
are  being  bred  for  a  combination  of  high  protein  and  high  oil. 

There  is  another  point  which  has  a  bearing  on  this  work,  namely,  we 
selected  a  variety  of  corn  of  average  composition;  and  from  this  we 
began  breeding  in  several  different  directions,  one  for  high  protein  and 
one  for  low  protein,  another  for  high  oil  and  still  another  for  low  oil. 
This  variety  of  corn  was  not  especially  high  in  protein  when  we  began 
with  it,  not  so  high,  in  fact,  as  some  other  varieties  which  we  were  growing 
at  the  time  and  which  are  now  being  bred  for  high  protein  by  some  of 
the  Illinois  seed  corn  breeders. 

For  information  concerning  Illinois  seed  corn  breeders  and  the 
varieties  of  corn  they  are  breeding,  the  reader  is  referred  to  their  secretary, 
Mr.  John  R.  Clisby,  Arcola,  Illinois. 


CORRECTION 

On  page  619,  under  the  heading  "Actual  Plan,"  the 
order  of  numbers  should  read:  4,  10,  16,  8,  14,  20,  4, 10, 
16,  8,  14,  20. 


UNIVERSITY  OF  ILLINOIS-URBANA 


